Pathogenesis

Caused by Rickettsia prowazekii; louse infected after feeding on rickettsemic person with typhus or during a recrudescent case; bites human to engage in blood meal and causes pruritic reaction on host skin; scratching by host causes crushing of lice and Rickettsia-laden excrement inoculated into wound

References

Ortonne JP (1990) The effects of ultraviolet exposure on skin melanin pigmentation. Journal of International Medical Research 18 Suppl 3:8C-17C